Variable speed driving mechanisms



Nov. 22, 1955 A. H. JOHNSON ET AL VARIABLE SPEED DRIVING MECHANISMS Filed March 27, 1951 )ven 725m ARTHUR HOWAR D JOHNSON ROY BAXENDALE BYCP Alla/nay United States Patent Ofifice 2,724,277 Patented Nov. 22, 1955 VARIABLE SPEED DRIVING MECHANISMS Arthur Howard Johnson, London, and Roy Baxendale, Hayes, England, assignors to Electric & Musical Industries Limited, Hayes, England, a British company Application March 27, 1951, Serial No. 217,768

Claims priority, application Great Britain March 31, 1950 1 Claim. (Cl. 74-199 said driving member and said turntable, a lever mounted for angular movement about the axis of said driving member, two further rotatable driving members mounted for angular movement with said lever, one of said furside of the axis of said first-mentioned driving member and the other of said further members being disposed on the other side of the axis of said first-mentioned driving member, a further rotatable idler member mounted on said lever, means urging said further rotatable idler member into engagement with said rotatable driving member and one of said further rotatable driving members and a still further rotatable idler member mounted on said lever, means urging said still further rotatable idler member into engagement with said rotatable driving member and the other of said two further rotatable driving members, said lever having one position in which said first-mentioned driving member is in driving engagement with said first mentioned idler member and said first-mentioned idler member is in engagement with said turntable to drive said turntable in one direction at a predetermined speed and with said further driving members out of engagement with said first-mentioned idler member, another position in which one of, said further driving members is in driving engagement with said first-mentioned idler member and said first-mentioned idler member is in engagement with said turntable to drive said turntable in said one direction at a speed different from said predetermined speed and with said first-mentioned idler member moved out of engagement with said first-mentioned driving memher and another position in which the other of said further driving members is in driving engagement with said first-mentioned idler member and said first-mentioned idler member is in engagement with said turntable to drive said turntable in said one direction and at a speed different from said predetermined speed or said different speed and with said first-mentioned idler member moved outof engagement with said first-men tioned driving member.

In order that the said invention may be clearly understood and readily carried into effect, it will now be more fully described with reference to the accompanying. drawings, in which the figure is a plan view of a variable speed driving mechanism suitable for use in ther rotatable driving members being disposed on one phonograph record playing apparatus for enabling the turntable to be driven at three different speeds Referring to the drawing, the mechanism comprises a base plate 1 suitably disposed with respect to the rim 2 of the turntable of the record playing apparatus, and on the underside of the base plate 1 is mounted a driving motor (not shown), the shaft 4 of which is vertically disposed and projects through an aperture in the base plate 1 and has a pulley 5 secured thereto.

The turntable 2 is driven by an idler wheel 7 which is urged into engagement with the turntable by a tension spring 28 anchored at one end to said base plate 1 and connected at the other end to one end of an arm 29 on which the wheel 7 is rotatably mounted, the other end of said arm 29 having a slot 30 embracing a pin 31 mounted on the base plate 1 to enable the wheel 7 to be displaced as hereinafter referred to. The spring 28 also normally urges the wheel 7 into engagement with the pulley 5. A lever 11 is mounted intermediate its ends for angular movement about the projecting part of the motor shaft 4 and carries .two loose driving wheels 14 and 15 arranged one on each side of the shaft 4 and having different diameters.

The pulley 5 on the motor shaft 4 is coupled to the driving wheels 14 and 15 through the medium of idler wheels 20 and 21 respectively mounted on stub shafts 22 and 23 which are carried respectively by rods 24 and 25 mounted for longitudinal movement in lugs 26 secured to lever 11. On each rod 24 and 25 there is provided a compression spring 24' and 25 respectively which bears at one end against one of the lugsy26 and at the other end against a collar 27 provided on the rod, so that under the action of the compression springs, the idler wheels 20 and 21 tend to be urged into engagement with the pulley 5 and with enlarged portions 14' and 15 of wheels 14 and 15 respectively. By virtue of the provision of the idler wheels 20 and 21 the pulley 5 and wheels 14 and 15 all rotate in the same direction.

In operation, if the lever 11 is in an angular position such that neither of the driving wheels 14 and 15 is in engagement with the idler wheel 7, the latter is pulled by the spring 28 into engagement with both the pulley 5 on the motor shaft 4 and the rim 2 of the turntable, so that when the motor is operating the motor shaft 4 drives the idler wheel 7 directly. Under these conditions the turntable may be arranged to rotate at for example 78 revolutions per minute, which is the normal speed for playing conventional records. The wheels 14 and 15 rotate continuously when the motor is running, due to their being coupled to the pulley 5 via the idler wheels 20 and 21. If the lever 11 is moved angularly in one direction, one of the wheels 14 or 15, say the wheel 14, engages the rim of the idler wheel 7 and moves the latter, against the action of the spring 28, out of engagement with the pulley 5. The idler wheel 7 thereupon ceases to be driven directly by the pulley 5 and is now driven, in the same direction as before, by the wheel 14, the diameter of the wheel 14 being such that the turntable now rotates at for example 33 revolutions per minute, which is a suitable speed for playing some forms of long-playing records. If the lever 11 is now moved angularly in the other direction, the wheel 14 is moved. out of engagement with the idler wheel 7 and the latter is moved under the action of spring 28 until it again engages the pulley 5 and is driven directly thereby. Upon a further angular movement of the lever 11 in said other direction, the wheel 15 engages the idler wheel 7 and moves it away from the pulley 5, the idler wheel 7 now being driven in the same direction as before by thewheel 15. The diameter of the wheel 15 may be such.for example that the turntable now rotates at 45 revolutions per minute, which is a suitable speed for playing other forms of long-playing records.

-Thus-aceording to thesetting of lever 11 the turntable Zi'S driVenat' one or other of three different speeds depending on whether it is driven directly by "the pulley 5 onthe'motor shaft or by one or other of rapidly/into engagement with the idler wheel 7 than is likelyto be the case when the lever 11 is actuatedby theoperator. 'In order to retain lever 11 in the desired position a-elick device is provided comprising an arm 32 'pivotally mounted at 33 on base plate 1 and carryinga pin 34 which under the action of a spring'35 connected-between the arm 32 and the base plate 1 is drawn into one or other of three recesses formed in the edge 'of lever 11 as shown. The arm 36 of lever 11 may be coupled to means for automatically bringing into-operation pick-ups suited to the different speeds of the turntable.

What we claim is:

A selectivethree-speed drive transmission mechanism fo'r=driving a turntable comprising a rotatable driving member, a turntable, a rotatable idler member, means mounting said idler member for movement transverse to its axis, meansto 'urge said idler-member into engagement with said driving member and said turntable, adever mounted for angular movement about the axis of said driving member, two further rotatable driving membersmounted for angular movement with said lever, one ofsaid further rotatable driving members bein'grdisposed on one side of the axis of said first-mentioned driving member and the other of said further members being disposed on the other side of the axis of said first-mentioned driving member, a further rotatable idler member mounted on said lever, means urging said further rotatable'idler member into'engagement with said rotatable driving member and one of said further rotatable driving members, and a still further rotatable idler member mounted on said lever, means urging said still further rotatable idler member into engagement with said rotatable driving member and the other of said two further rotatable drivingmembers, said lever having one position in which said-first-mentioned driving member is in driving engagement with said first mentioned idler member and said first-mentioned idler member is in engagement with said turntable to drive said turntable in one direction ata predetermined speed and with said further driving me'mbers out of engagement with said first-mentioned idler member, another position in which one of said further driving members is in driving engagement with said first-mentioned idler member and said first-mentioned idler member is in engagement With said turntable to drive said turntable in said one direction at a speed different from s'aidpredeter'mined speed and with said first-mentioned idler member moved out' of engagement with said first-mentioned driving member and another position in which the other of said further driving members ism driving engagement with saidfirstmentioned idler member Zilld said fift-filliilfid idll' member is in engagement with said turntable to drive said turntable in said one directionandat a speed different from said predetermined speed or said different s eed and with s'aid'first-mentione'd idler member moved out of engagement with said first-mentioned driving member;

References Citedin the file of this'patent 

